Wafer-level packaging for solid-state transducers and associated systems and methods

ABSTRACT

Wafer-level packaging of solid-state transducers (“SSTs”) is disclosed herein. A method in accordance with a particular embodiment includes forming a transducer structure having a first surface and a second surface opposite the first surface, and forming a plurality of separators that extend from at least the first surface of the transducer structure to beyond the second surface. The separators can demarcate lateral dimensions of individual SSTs. The method can further include forming a support substrate on the first surface of the transducer structure, and forming a plurality of discrete optical elements on the second surface of the transducer structure. The separators can form barriers between the discrete optical elements. The method can still further include dicing the SSTs along the separators. Associated SST devices and systems are also disclosed herein.

TECHNICAL FIELD

The present technology is related to solid-state transducers and methodsof manufacturing solid-state transducers. In particular, the presenttechnology relates to wafer-level packaging for solid-state transducersand associated systems and methods.

BACKGROUND

Mobile phones, personal digital assistants (“PDAs”), digital cameras,MP3 players, and other electronic devices utilize light-emitting diodes(“LEDs”), organic light-emitting diodes (“OLEDs”), polymerlight-emitting diodes (“PLEDs”), and other solid-state transducerdevices for backlighting. Solid-state transducer devices are also usedfor signage, indoor lighting, outdoor lighting, and other types ofgeneral illumination. FIG. 1 shows a cross-sectional view of aconventional LED device 10 with vertical contacts. The LED device 10includes a support substrate 20 carrying an LED structure 12 that has anactive region 14 (e.g., containing gallium nitride/indium galliumnitride (GaN/InGaN) multiple quantum wells (“MQWs”)) positioned betweenN-type gallium nitride (“N-GaN”) 16 and P-type gallium nitride (“P-GaN”)18. The LED device 10 also includes a first contact 22 on the P-type GaN18 and a second contact 24 opposite the first contact 22 on the N-typeGaN 16. As further shown in FIG. 1, the LED device 10 can also include aconverter material 26 and an encapsulant 28 positioned over one anotheron the LED structure 12. In operation, the LED structure 12 can emit afirst emission (e.g., blue light) that stimulates the converter material26 (e.g., phosphor) to emit a second emission (e.g., yellow light). Thecombination of the first and second emissions can generate a desiredcolor of light (e.g., white light).

The LED structure 12 can be formed on a semiconductor wafer thatincludes several individual LED die. During conventional manufacturingprocesses, the wafers are cut into separate the LED die, and then theindividual LED die are packaged and tested. For example, the LEDstructure 12 can be diced from a wafer-level LED structure and attachedto the support substrate 20. The converter material 26 and theencapsulant 28 can then be formed over the front of the singulated LEDstructure 12.

A challenge associated with such conventional LED packaging is thatforming the converter material 26 and the encapsulant 28 on singulateddie requires precise handling that increases manufacture time and leadsto increased packaging costs. Another concern is that mounting each LEDdie to a separate support substrate is also time consuming and requiresmore precise handling. Additionally, LED devices generally produce asignificant amount of heat, and the different coefficients of thermalexpansion between the LED structure and the underlying support substratecan result in delamination between the two or other damage to thepackaged device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional diagram of an LED device inaccordance with the prior art.

FIG. 2A is a schematic top plan view of a portion of a wafer-levelassembly having a plurality of solid-state transducer die in accordancewith an embodiment of the present technology.

FIG. 2B is a schematic cross-sectional view of the wafer-level assemblyof FIG. 2A taken view taken substantially along the line 2B-2B.

FIGS. 3A-3G are schematic cross-sectional views of a method ofmanufacturing solid-state transducers in accordance with an embodimentof the present technology.

FIGS. 4A-4C are schematic cross-sectional views of wafer-levelassemblies having a plurality of solid-state transducer die inaccordance with other embodiments of the present technology.

FIG. 5 is a schematic view of a system that incorporates a packagedsolid-state transducer device in accordance with embodiments of thepresent technology.

DETAILED DESCRIPTION

Specific details of several embodiments of wafer-level packaging forsolid-state transducers (“SSTs”) and associated systems and methods aredescribed below. The term “SST” generally refers to solid-state devicesthat include a semiconductor material as the active medium to convertelectrical energy into electromagnetic radiation in the visible,ultraviolet, infrared, and/or other spectra. For example, SST devicesinclude solid-state light emitters (e.g., LEDs, laser diodes, etc.)and/or other sources of emission other than electrical filaments,plasmas, or gases. The term SST can also include solid-state devicesthat convert electromagnetic radiation into electricity. Additionally,depending upon the context in which it is used, the term “substrate” canrefer to a wafer-level substrate or to a singulated device-levelsubstrate. A person skilled in the relevant art will also understandthat the technology may have additional embodiments, and that thetechnology may be practiced without several of the details of theembodiments described below with reference to FIGS. 2A-5.

FIG. 2A is a schematic top plan view of a portion of a wafer-levelassembly 200 (“assembly 200”) having a plurality of SSTs 202 (identifiedindividually as a first—sixth SSTs 202 a-f, respectively) in accordancewith an embodiment of the present technology, and FIG. 2B is a schematiccross-sectional view of the assembly 200 taken along lines 2B-2B of FIG.2A. As shown in FIG. 2B, the assembly 200 can include a supportsubstrate 204, a transducer structure 206, discrete converter elements208, and discrete cover elements 210 positioned sequentially on oneanother. The converter elements 208 and cover elements 210 can defineoptical elements. For example, the cover elements 210 can be lenses. Inseveral examples, each converter element 208 and corresponding coverelement 210 can be combined into a single integrated converter/coverelement. In other embodiments, each cover element 210 can be positionedover multiple SSTs 202, one cover element 210 can be positioned over theentire wafer-level assembly 200, or the cover elements 210 can beomitted. Similarly, the converter elements 208 can be positioned overmore than one SST 202 or can be omitted. The assembly 200 can alsoinclude a plurality of separators 222 that are aligned with dicing lanes218-218 to demarcate the boundaries of the individual SSTs 202. Forclarity, the cover elements 210 are not shown in FIG. 2A such that theunderlying features of the assembly 200 are visible.

The support substrate 204 of the assembly 200 can be made from a metalthick enough to support the transducer structure 206 and limit theamount of bowing of the support substrate 204. For example, the supportsubstrate 204 can be made from copper that has a thickness betweenapproximately 50 μm and 300 μm. In other embodiments, the supportsubstrate 204 can be made from other metallic materials (e.g., gold,aluminum, etc.) and/or differ in thickness. In several embodiments, themetal support substrate 204 can be configured to have a coefficient ofthermal expansion generally similar to that of the transducer structure206 to decrease the likelihood of delamination between the two.Additionally, the metal support substrate 204 can function as a heatsink to decrease the operating temperature of the SSTs 202. In otherembodiments, the support substrate 204 can be made from silicon,sapphire, and/or other nonmetallic materials.

As shown in FIG. 2B, the transducer structure 206 can include a firstsemiconductor material 223, an active region 224, and a secondsemiconductor material 226 stacked sequentially on one another. Thefirst semiconductor material 223 can be a doped semiconductor material,for example, a P-type semiconductor material (e.g., P-GaN) proximate afirst surface 216 a of the transducer structure 206 and electricallycoupled to a plurality of first contacts 212 corresponding to theindividual SSTs 202. The second semiconductor material 226 can be adoped semiconductor material, for example, an N-type semiconductormaterial (e.g., N-GaN) proximate a second surface 216 b of thetransducer structure 206 and electrically coupled to second contacts 214corresponding to individual SSTs 202. This configuration is suitable fortransducer structures that are formed on, for example, silicon orpolycrystalline aluminum nitride growth substrates, and then removedfrom such growth substrates after being attached to the supportsubstrate 204. In other embodiments, such as when the transducerstructure 206 is formed on a sapphire growth substrate, the dopedregions of the semiconductor material (i.e., the P-GaN and N-GaN) can bereversed. The active region 224 between the first and secondsemiconductor materials 223 and 226 can include a single quantum well(“SQW”), MQWs, and/or a single grain semiconductor material (e.g.,InGaN). In other embodiments, the transducer structure 206 can includeother suitable semiconductor materials, such as gallium arsenide (GaAs),aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP),etc.), and/or other semiconductor materials.

In several embodiments, the first contacts 212 on the first surface 216a of the transducer structure 206 can include a reflective material toredirect emissions (e.g., light) back through the transducer structure206 toward the second surface 216 b. For example, the first contacts 212can include silver (Ag), copper (Cu), aluminum (Al), Nickel (Ni),tungsten (W), and/or other suitable reflective materials. In otherembodiments, the first contacts 212 can be made from non-reflectivematerials and separate reflective elements can be positioned on thefirst surface 216 a of the transducer structure 206 to redirectemissions toward the second surface 216 b. In further embodiments, theSSTs 202 do not include reflective elements.

Referring to FIG. 2A, the second contacts 214 can each include aplurality of fingers 221 connected to one another by one or more crossmembers 223 and coupled to one or more current routers 225. Such aconfiguration enhances current spreading of the SSTs 202. The currentrouters 225 are positioned outside of the converter elements 208 and thecover elements 210 to allow for subsequent electrical connection (e.g.,via wirebonds, solder bumps, etc.). The fingers 221 and/or the crossmembers 223 can individually include an elongated structure as shown inFIG. 2A and/or other suitable structures. In other embodiments, thesecond contacts 214 can have other suitable configurations. In severalembodiments, the second contacts 214 are made from copper (Cu), aluminum(Al), silver (Ag), gold (Au), platinum (Pt), and/or other suitableelectrically conductive materials. In other embodiments, the secondcontacts 214 can be a transparent electrode constructed from indium tinoxide (“ITO”), aluminum zinc oxide (“AZO”), fluorine-doped tin oxide(“FTO”), and/or other substantially transparent and conductive oxides.

The converter elements 208 can be formed over the second contacts 214and the second surface 216 b of the transducer structure 206 such thatemissions (e.g., light) from the transducer structure 206 irradiate theconverter elements 208. The irradiated converter elements 208 can emit alight of a certain quality (e.g., color, warmth, intensity, etc.).Accordingly, the converter elements 208 can include a phosphorcontaining a doped yttrium aluminum garnet (YAG) (e.g., cerium (III)) ata particular concentration for emitting a range of colors underphotoluminescence. In other embodiments, the converter elements 208 caninclude silicate phosphor, nitrate phosphor, aluminate phosphor, and/orother suitable wavelength conversion materials. The converter elements208 can have a generally rectangular cross-sectional shape as shown inFIG. 2B or have other suitable cross-sectional shapes (e.g., oval,irregular, etc).

Referring back to FIG. 2B, the cover elements 210 can be positioned overthe converter elements 208 and transmit emissions generated by thetransducer structure 206 and/or the converter elements 208. In theillustrated embodiment, the cover elements 210 are formed into generallyhemispherical lenses on each of the SST 202. In other embodiments, thecover elements 210 can be formed into lenses having different shapes tocollimate, scatter, and/or otherwise diffract light or other emissionsfrom the transducer structure 206 and the converter elements 208.

The cover elements 210 can include a transmissive material made fromsilicone, polymethylmethacrylate (PMMA), resin, or other suitabletransmissive materials. In selected embodiments, the cover elements 210includes an additional converter element (not shown) that emits light ata different frequency than the converter elements 208 proximate thetransducer structure 206.

The separators 222 shown in FIG. 2B are defined by protrusions 220 thatextend through the transducer structure 206 and project beyond thesecond surface 216 b of the transducer structure 206. For example, inselected embodiments, the protrusions 220 can extend from the firstsurface 216 a of the transducer structure 206 beyond the cover elements210 and have a height between approximately 10 μm and 30 μm. In otherembodiments, the protrusions 220 can have greater or smaller heightsand/or vary in height across the assembly 200. Additionally, the shapeof the protrusions 220 may vary from that shown in FIGS. 2A and 2B. Inillustrated embodiment, for example, the protrusions 220 have agenerally V-shaped cross-section (FIG. 2B) and form a border (FIG. 2A)around the individual SSTs 202. The border around the individual SSTs202 can be rectangular, circular, oval, hexagonal, irregular, and/or anyother suitable shape. In other embodiments, the protrusions 220 can haveother suitable cross-sectional shapes.

As shown in FIG. 2B, each protrusion 220 can include one or morematerials. In the illustrated embodiment, for example, the protrusions220 include an outermost dielectric isolator 228, a barrier material 230(e.g., WTi, Ta, TaN), an optional seed material 232 (e.g., Cu, Ni), anda portion of the support substrate 204. In selected embodiments, thedielectric isolator 228 can be an oxide passivation layer made fromsilicon oxide (SiO₂) or other suitable material that electricallyisolates portions of the transducer structure 206 from one another thatcorrespond to the individual SSTs 202. In other embodiments, theprotrusions 220 can include additional materials and/or some of thematerials shown in FIG. 2B can be omitted.

The protrusions 220 can provide a barrier between individual SSTs 202that allows discrete converter elements 208 and discrete cover elements210 to be formed over the individual SSTs 202 without spilling onto orotherwise contacting the adjacent SSTs 202. Accordingly, in selectedembodiments, different converter elements 208 and/or cover elements 210can be formed on the individual SSTs 202 based on desired performanceparameters (e.g., color, intensity, etc.). The SSTs 202, therefore, canbe fully packaged and subsequently tested at the wafer-level beforedicing, thereby eliminating the need for precise handling of the dicedSSTs 202 during packaging and testing. Additionally, as shown in FIG.2A, the protrusions 220 can demarcate a dicing pattern betweenindividual SSTs 202 and thereby serve as guides during dicing.

FIGS. 3A-3H illustrate a process of forming an embodiment of the SSTs202 of FIGS. 2A and 2B in accordance with an embodiment of the presenttechnology. FIG. 3A shows a stage of the process after the transducerstructure 206 has been formed on a growth substrate 334. The growthsubstrate 334 can be made from silicon, polycrystalline aluminumnitride, sapphire, and/or other suitable materials. The transducerstructure 206 can be formed via metal organic chemical vapor deposition(“MOCVD”), molecular beam epitaxy (“MBE”), liquid phase epitaxy (“LPE”),and/or hydride vapor phase epitaxy (“HVPE”). In other embodiments, atleast a portion of the transducer structure 206 may be formed usingother suitable epitaxial growth techniques.

Additionally, as shown in FIG. 3A, a plurality of trenches 338 can beformed through the transducer structure 206 to separate the transducerstructure 206 into mesas 336. The mesas 336 can define the lateraldimensions of the subsequently formed SSTs 202 (FIG. 3F), and thetrenches 338 can have dimensions and shapes that correspond to theshapes and dimensions of the subsequently formed protrusions 220 (FIG.3D). For example, as shown in FIG. 3A, the trenches 338 can havegenerally V-shaped cross-sections with sidewalls 344 that extend fromthe first surface 216 a of the transducer structure 206 into a portionof the growth substrate 334. The trenches 338 can be formed bypositioning a mask (not shown) over the areas above the mesas 336 andetching (e.g., wet etch, dry etch, etc.) through the exposed portions ofthe transducer structure 206 and the growth substrate 334. In otherembodiments, the trenches 338 can be formed using other suitable removalmethods. In further embodiments, the trenches 338 can be formed afterthe first contacts 212 (FIG. 3B) are formed on the first surface 216 aof the transducer structure 206 such that the sidewalls 344 of thetrenches 338 extend through the first contacts 212, the transducerstructure 206, and a portion of the growth substrate 334.

FIG. 3B illustrates a stage of the process after the first contacts 212,the separators 222, and the support substrate 204 are formed over thefirst surface 216 a of the transducer structure 206. One or morematerials can partially or fully fill the trenches 338 to form theseparators 222. In the embodiment shown in FIG. 3B, for example, thedielectric isolators 228 are formed along the sidewalls 344 of thetrenches 338, the first contacts 212 are formed on the mesas 336, andthe barrier and seed materials 230 and 232 are sequentially formed overthe dielectric isolators 228 and the first contacts 212. Each materialcan be formed using chemical vapor deposition (“CVD”), physical vapordeposition (“PVD”), atomic layer deposition (“ALD”), spin coating,patterning, and/or other suitable techniques known in the semiconductorfabrication arts. The dielectric isolators 228 can be formed bydepositing a conformal dielectric and then removing the portions of thedielectric from the mesas 336 using an etching or chemical-mechanicalprocess. In other embodiments, the dielectric isolators 228 can beformed by positioning a mask over the mesas 336 and depositing thedielectric in the trenches 338 and/or using other suitable formationtechniques. In further embodiments, additional materials can be addedand/or one or more of the materials can be omitted. For example, thetrenches 338 can be filled entirely with a dielectric material insteadof a conformal dielectric.

In other embodiments, the first contacts 212 can completely cover themesas 336 and the dielectric isolators 228. Such a construction can beused when the dielectric isolators 228 are made from a substantiallytransparent material (e.g., silicon oxide, silicon nitride, etc.) andthe first contacts 212 are made of a reflective material (e.g., silver,gold, etc.) such that the first contacts 212 can redirect emissions backthrough the dielectric isolators 228 and the transducer structure 206.

If made of metal, the support substrate 204 can be plated onto the seedmaterial 232. Plating the metal substrate 204 over the first side 216 aof the transducer structure 206 eliminates the need forthermo-compression and inter-metallic compound bonding and enables theassembly 200 to have a larger diameter because the support substrate 204inhibits bowing of the support substrate 204. In several embodiments,for example, the assembly 200 can be at least four inches in diameter,and in many cases between six and eight inches in diameter without undobowing. In other embodiments, the support substrate 204 can include anonmetallic material and/or be attached to the assembly 200 using othersuitable methods.

FIG. 3C illustrates another stage in the process after the assembly 200is inverted and a carrier substrate 340 is attached to the supportsubstrate 204. The carrier substrate 340 can be made from silicon and/orother suitable substrate materials that can support the assembly 200during subsequent fabrication stages. The carrier substrate 340, forexample, can provide a temporary platform that can reduce or preventbowing of the wafer through the fabrication. The carrier substrate 340can therefore be attached to the support substrate 204 with a temporaryadhesive 342 (e.g., WaferBOND™ HT-10.10 from Brewer Science, Inc. ofRolla, Mo.) that can bond the two substrates 204 and 340 together forsubsequent processing, and then be manipulated to separate thesubstrates 204 and 340 before or after dicing of the SSTs 202. In otherembodiments, the carrier substrate 340 can be omitted during processing.

FIG. 3D illustrates a subsequent stage in the process after the growthsubstrate 334 has been removed from the assembly 200. As shown in FIG.3D, the growth substrate 334 can be removed such that at least a portionof the individual separators 222 remains. As a result, the separators222 project beyond the second side 216 b of the transducer structure 206to form the protrusions 220. The growth substrate 334 can be removed bybackgrinding, etching, and/or other suitable removal methods. Forexample, removing the growth substrate 334 can include backgrinding thegrowth substrate 334 to the ends of the separators 222, and etching theremaining portions of the growth substrate 334 away from the sidewalls334 and the second surface 216 b of the transducer structure 206.

FIG. 3E shows a further stage in the process after the second contacts214, the converter elements 208, and the cover elements 210 have beenformed over the second surface 216 b of the transducer structure 206.The second contacts 214 can be formed using CVD, ALD, PVD, patterningand/or other suitable formation techniques. Optionally, the secondsurface 216 b can be roughened before the second contacts 214 areformed. In selected embodiments, such as the embodiment shown in FIG.2A, the second contacts 214 can include interconnected fingers 221,cross members 223, and current routers 225 to enhance current spreading.In other embodiments, the second contacts 214 can have differentstructures.

The converter elements 208 and the cover elements 210 can be formed overthe second surface 216 b of the transducer structure 206 using inkjetting techniques, spin coating and patterning, CVD, PVD, and/or othersuitable deposition techniques. In other embodiments, the cover elements210 can be pre-formed into lenses that are subsequently attached overthe individual SSTs 202. During such packaging, the protrusions 220 canprovide barriers between the SSTs 202 that allow the formation ofdiscrete portions of the converter elements 208 and the cover elements210 over the individual SSTs 202, without the converter elements 208 andthe cover elements 210 spreading onto or otherwise contacting theadjacent SSTs 202. This enables selective deposition of differentconverter elements 208 and/or different cover elements 210 overadjoining SSTs 202.

FIGS. 3F and 3G illustrate additional stages of the process after thecarrier substrate 340 has been removed, and the assembly 200 has beendiced along the dicing lanes 218-218. The carrier substrate 340 can beremoved by backgrinding, etching, de-bonding, and/or other suitableremoval techniques. When heat is used to de-bond the carrier substrate340 from the support substrate 204, the cover elements 210 may be formedafter the carrier substrate 340 has been de-bonded.

Before or after removal of the carrier substrate 340, the assembly 200can undergo peak wavelength testing and/or testing of performanceparameters (e.g., intensity) of the individual SSTs 202. Suchwafer-level testing can be performed on the partially or fully packagedSSTs 202 such that they can be pre-sorted according to predeterminedtest limits in a process known as “binning ” For example, the assembly200 can also undergo lambda testing before the converter elements 208are deposited. The converter elements 208 can then be selectedaccordingly for individual SSTs 202 to generate a generally uniformcolor across the assembly 200 and thereby simplify binning Thewafer-level testing of the SSTs 202 also requires less precise handlingthan testing the diced SSTs 202.

The dicing lanes 218-218 can be aligned with the separators 222. Asshown in FIG. 3G, dicing along the dicing lanes 218-218 forms SSTs 202that have peripheral portion 346 defined by the separators 222 thatborders the transducer structure 206, converter elements 208, and thecover elements 210. In other embodiments, the separators 222 can beremoved from the SST 202 during dicing or subsequent removal processes.The packaged SST 202 is ready for use after dicing, and can thus beimmediately incorporated into devices for backlighting, generalillumination, and/or other emissions in the ultraviolet, visible,infrared, and/or other spectra. During operation, the metal supportsubstrate 204 can enhance the thermal performance of the SSTs 202.

FIGS. 4A-4C are schematic cross-sectional views of wafer-levelassemblies 400A-C (“assemblies 400A-C”) in accordance with otherembodiments of the technology. Several features of the assemblies 400A-Care generally similar to the features of the assembly 200 describedabove with reference to FIGS. 2A-3G. For example, the assemblies 400A-Cinclude the support substrate 204, the transducer structure 206, theconverter elements 208, and the cover elements 210. However, in theembodiment illustrated in FIG. 4A, the converter elements 208 and thecover elements 210 are combined as a single optical element over eachSST 202. Additionally, as shown in FIGS. 4A-4C, rather than the V-shapedprotrusions 220 described above, the assemblies 400A-C includeprotrusions 220 having a rectangular, a trapezoidal, and an oval crosssection in FIGS. 4A-4C, respectively. However, no one type of device islimited to a particular shape of protrusion 220. In other embodiments,the protrusions 220 can also include other suitable cross-sectionalshapes. As shown in FIGS. 4A-4C, the protrusions 220 extend beyond thesecond surface 216 b of the transducer structure 206 and define theseparators 222 that demarcate the individual SSTs 202. As describedabove, the protrusions 220 can facilitate wafer-level packaging andtesting of the SSTs 202.

Any one of the packaged SST described above with reference to FIGS.2A-4C can be incorporated into any of a myriad of larger and/or morecomplex systems, a representative example of which is system 500 shownschematically in FIG. 5. The system 500 can include an SST device 510, apower source 520, a driver 530, a processor 540, and/or other subsystemsor components 550. The resulting system 500 can perform any of a widevariety of functions, such as backlighting, general illumination, powergeneration, sensors, and/or other functions. Accordingly, representativesystems 500 can include, without limitation, hand-held devices (e.g.,cellular or mobile phones, tablets, digital readers, and digital audioplayers), lasers, photovoltaic cells, remote controls, computers, andappliances (e.g., refrigerators). Components of the system 500 may behoused in a single unit or distributed over multiple, interconnectedunits (e.g., through a communications network). The components of thesystem 500 can also include local and/or remote memory storage devices,and any of a wide variety of computer-readable media.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. For example, even though only one converter element 208 isshown in the Figures, in other embodiments, the assemblies 200 and400A-C and/or the individual SSTs 202 may include two, three, four, orany other suitable number of converter elements with different emissioncenter wavelengths and/or other characteristics. Additionally, themethod of forming the SSTs described above with reference to FIGS. 3A-3Gincludes forming trenches 338 before forming the first contacts. Inother embodiments, the first contacts 212 can be formed on thetransducer structure 206, and the trenches 338 can be subsequentlyformed through the first contacts 212, the transducer structure 206, anda portion of the growth substrate 334. Certain aspects of the newtechnology described in the context of particular embodiments may becombined or eliminated in other embodiments. For example, a assembly inaccordance with an embodiment of the technology can include varyingshapes of protrusions 220, such as alternating the V-shaped protrusionsshown in FIGS. 2B-3G and the oval-shaped protrusions shown in FIG. 4C.Additionally, while advantages associated with certain embodiments ofthe new technology have been described in the context of thoseembodiments, other embodiments may also exhibit such advantages, and notall embodiments need necessarily exhibit such advantages to fall withinthe scope of the technology. Accordingly, the disclosure and associatedtechnology can encompass other embodiments not expressly shown ordescribed herein.

1. A method of forming solid-state transducers (SSTs), the methodcomprising: forming a transducer structure on a growth substrate, thetransducer structure having a first surface opposite a second surface,wherein the second surface is proximate to the growth substrate; forminga plurality of trenches extending through the transducer structure andat least partially through the growth substrate; forming separators inthe trenches that demarcate individual SSTs; forming a support substrateover the first surface of the transducer structure and the separators;and removing the growth substrate from the second surface of thetransducer structure such that at least a portion of the separatorsremains, the separators forming a plurality of protrusions that extendbeyond the second surface of the transducer structure.
 2. The method ofclaim 1 wherein: forming the separators comprises depositing adielectric isolator and a metallic material sequentially in thetrenches; and forming the support substrate comprises plating a metalsubstrate on the metallic material, the metal substrate extendingpartially into the trenches.
 3. The method of claim 2, furthercomprising: forming first contacts on the first surface of thetransducer structure before forming the support substrate; formingsecond contacts on the second surface of the transducer structure afterremoving the growth substrate; forming converter elements over thesecond surface of the transducer structure and the second contacts,wherein individual converter elements are separated by the protrusions;and dicing along lines aligned with the protrusions to separate theindividual SSTs.
 4. The method of claim 1, further comprising formingconverter elements over the first surface of the transducer structure,portions of the converter elements being separated by the protrusions.5. The method of claim 4, further comprising: measuring wavelengths ofthe individual SSTs before forming the converter elements; and selectingthe converter elements for each SST according to the measured wavelengthof the SST to generate a generally uniform color across the plurality ofthe SSTs.
 6. The method of claim 1, further comprising forming coverelements over the first surface of the transducer structure, wherein theprotrusions separate individual cover elements.
 7. The method of claim 6wherein forming the cover elements comprises positioning lenses over theindividual SSTs.
 8. The method of claim 1, further comprising: formingconverter elements over the second surface of the transducer structure,wherein individual converter elements are separated by the protrusions;and forming cover elements over the converter elements, whereinindividual cover elements are separated by the protrusions.
 9. Themethod of claim 1, further comprising: testing the individual SSTsbefore dicing the SSTs; and dicing the SSTs along dicing lanes, whereinthe dicing lanes are aligned with the protrusions.
 10. The method ofclaim 1 wherein the SSTs are configured to emit electromagneticradiation in at least one of the ultraviolet spectrum, the visiblespectrum, and the infrared spectrum.
 11. The method of claim 1, furthercomprising temporarily bonding a carrier substrate to the supportsubstrate before removing the growth substrate.
 12. A method of formingsolid-state transducers (SSTs), the method comprising: forming atransducer structure having a first surface and a second surfaceopposite the first surface; forming a plurality of separators thatextend through the transducer structure, wherein the separators extendfrom at least the first surface of the transducer structure and projectbeyond the second surface, wherein the separators demarcate individualSSTs; forming a support substrate on the first surface of the transducerstructure; forming discrete optical elements on the second surface ofthe transducer structure, wherein the separators form barriers betweenthe discrete optical elements; and dicing the SSTs along the separators.13. The method of claim 12 wherein forming the discrete optical elementscomprises forming discrete converter elements on the second surface ofthe transducer structure, wherein the separators form barriers betweenthe discrete converter elements.
 14. The method of claim 12 whereinforming the discrete optical elements comprises forming discrete coverelements on the second surface of the transducer structure, wherein theseparators form barriers between the discrete cover elements.
 15. Themethod of claim 12 wherein forming the plurality of separatorscomprises: forming a plurality of trenches on the first surface of thetransducer structure, wherein the trenches have sidewalls that extendfrom at least the first surface of the transducer structure beyond thesecond surface and into an underlying growth substrate; depositing atleast one of a dielectric isolator, a barrier material, and a seedmaterial into the trenches; and removing the growth substrate from thesecond surface of the transducer structure and from the sidewalls toform protrusions above the second surface of the transducer structure.16. The method of claim 15 wherein forming the trenches furthercomprises plating a portion of the support substrate to the seedmaterial.
 17. The method of claim 12, further comprising testing theindividual SSTs before dicing.
 18. The method of claim 17 wherein:testing the individual SSTs comprises measuring the wavelengths of theindividual SSTs before forming the optical elements; and the methodfurther comprises selecting the optical elements for each SST accordingto the measured wavelength.
 19. The method of claim 12 wherein formingthe support substrate comprises plating a metal substrate over the firstsurface of the transducer structure, wherein the metal substrate has athickness between approximately 50 gm and approximately 300 pm.
 20. Themethod of claim 12 wherein the SSTs are configured to emitelectromagnetic radiation in at least one of the ultraviolet spectrum,the visible spectrum, and the infrared spectrum. 21-33. (canceled)